Tamper proof watch cases

ABSTRACT

A watch case comprises a bezel frame to which a glass detachable only from the inside and a back cover are secured, and tamperproof means comprising a small radial blind hole formed in said cover and engageable by means of a suitable tool, and a plug inserted to be engaged by a screw-threaded extraction rod, said plug being provided with a breakable cap covering said tapped hole and flush with the outer surface of the back cover.

United States Patent Piquerez, deceased et al.

TAMPER PROOF WATCH CASES Inventors: Ervin Piquerez, deceased, late of2854 Bassecourt, Switzerland; by Ami Scholler, 3, rue Hugi, Bienne; byEdouard Bandelier, l0 Neubadrain, 4102 Binningen, both of Switzerland EFiled: June 7, 1971 Appl. No; 150,408

Foreign Application Priority Data June 9, 1970 Switzerland ..8600/7O US.Cl. ..58/88 R Int. Cl...... ..G04b 37/00 Field of Search ..58/88, 90 R,105

[ 51 Aug. 15, 1972 [56] References Cited UNITED STATES PATENTS l,940,289l2/l933 Bateman ..58/90 R 3,505,807 4/ I970 Piqueraz ..58/90 R 3,555,812l/l97l Piqueraz 58/90 R Primary Examiner-Richard B. Wilkinson AssistantExaminer-George H. Miller, Jr. Att0rney-R0bert E. Burns et al.

[ ABSTRACT A watch case comprises a bezel frame to which a glassdetachable only from the inside and a back cover are secured, andtamper-proof means comprising a small radial blind hole formed in saidcover and engageable by means of a suitable tool, and a plug inserted tobe engaged by a screw-threaded extraction rod, said plug being providedwith a breakable cap covering said tapped hole and flush with the outersurface of the back cover.

7 Clains, 3 Drawing Figures Patented Aug. 15, 1972 2 Sheets-Sheet l l II f I l..||.|| I I I I I ll.

Patented Aug. 15, 1972 3,683,615

2 Sheets-Sheet 2 FIG.2 13 12 TAMPER PROOF WATCH CASES The presentinvention relates to watch cases in general and has specific referenceto tamper-proof watch cases.

The trend towards the putting of increasingly expensive watch movementson the market, notably of quartz-type electronic movements, makes itnecessary to provide means for preventing persons other than skilledrepairers to have access to these movements. It is therefore necessaryto enable these qualified repairers to positively ascertain whether ornot a watch case has beenpreviously opened by an unqualified and/orunauthorized person. It has already been established that the bestsolution for exerting this supervision consists in providing an elementsuch that the case can not be opened unless this element is destroyed.

Thus, a known proposition consisted in utilizing a low-melting materialcast on at least one portion of the place where the tool necessary fordisassembling the component elements of the case must be inserted, sothat the tool could not be inserted unless said material was removed,thus providing a tamper-proof seal enabling a repairer to check whetherthe case had previously been opened or not. However, even an unskilledperson is capable of replacing this material, so that it becomes verydifficult to ascertain whether the case was opened or not.

Another known solution applicable to a cup-shaped case bottom consistsin assembling the cup-shaped bottom with the glass by means of a ring ofrelatively soft or ductile material which cannot be removed unless it isdestroyed, the replacement of this ring requiring the use of a specialtool. However, this solution is only applicable to a particular type ofwatch case with a shouldered glass insert. Furthermore, a false frame orbezel must be fitted to conceal the ring.

Under these conditions another solution applicable to watch cases withinsert bottom or back cover, which meets the desired requirements, mustbe found, i.e. a device the disassembling of which necessarily involvesits partial or complete destruction, and which can be manufactured onlywith great difficulty by persons other than skilled and qualifiedrepairers.

According to the invention, there is provided a watch casecomprising amain body portion and a cover removably fitted on the main body portion,a recess in said cover forming gripping means for cooperation with coverremoval means, and a member removably blocking said recess to normallyprevent cooperation thereof with removal means, said member comprisingmeans which must be at least partially destroyed for removal of themember from the recess.

The accompanying drawings illustrate on considerably enlarged scales twotypical embodiments of the invention. In the drawings:

FIG. 1 illustrates in fragmentary section a first embodiment;

FIG. 2 is a detail view of the composite plug utilized in thearrangement of FIG. 1, and

FIG. 3 illustrates a modified embodiment of the plug of FIG. 2.

The watch case illustrated in FIG. 1 comprises a bezel-frame 1 in whichare retained, on the one hand, a glass 2 by means of an O-ring 3engaging a pair of facing grooves 4, 5 formed in the bezel-frame l andglass 2 so as to interlock these members while sealing the jointtherebetween and, on the other hand, an inner ring la. The glass 2 isformed with a bevel 6 for safely preventing the insertion of anextraction tool so that the glass cannot be removed unless a pressure isexerted on its inner surface. The case 1 is closed by a bottom cover 7secured to the bezel-frame 1 in the same manner as the glass 2 by meansof an O-ring 8.

However, this bottom cover 7 can be removed by pulling same outwards,but the only gripping means provided thereon consists of a hole 9 formedradially therein and normally closed by a plug 10 flush with the outersurface of this bottom cover 7, so that to remove this cover it isnecessary firstly to free the hole 9 by extracting the plug 10.

The plug 10 shown on a larger scale in FIG. 2 comprises a metal body orpiston 11 of a diameter slightly inferior to the diameter of said hole 9and formed with an annular groove 12 in which an O-ring 13 is fitted;when compressed, this O-ring 13 will retain the plug 10 in its hole 9.The body 11 further comprises a tapped blind hole 14 in whichascrew-threaded pull-out rod can be engaged when it is desired toextract the plug 10 from the hole 9. This tapped hole 14 is covered by acap 15 for example of mineral glass sealed by cementing or melting onthe metal body 11. Under these conditions, it is clear that no accesscan be had to the tapped hole 14 unless the glass-cap 15 is firstlybroken. Of course, this cap 15 may consist of any other suitablematerial, such as organic glass, synthetic glass or other plasticmaterial.

To open the watch case the following procedure is adhered to: the cap 15is firstly broken, and a rod (not shown) having a screw-threaded endcorresponding to the tapped hole 14 is introduced into this hole, andthe plug 10 is extracted together with the remaining frag ments of theglass cap 15. Then, a stud-rod is inserted and the portion thereof whichemerges from the hole 9 constitutes a convenient gripping means foropening the bottom or back cover of the watch case. Upon completion ofthe repair or service work, the back cover is refitted in position andanother capped plug is force fitted into the hole 9. Since this plug isflush with the outer surface of back cover 7, it cannot be tampered withand removed without breaking the cap.

FIG. 3 illustrates a modified embodiment of the plug which consists of acylindrical metal body 16 formed with a tapped extraction hole 17covered by a cap 18 of resilient synthetic material. The edge of thissocketshaped cap 18 comprises a shallow bead 19 having a diameter (whenoutside the hole 9) slightly greater than the diameter of this holes, sothat when the plug is force-fitted into the hole 9 the bead 19 iscompressed radially inwards. To permit the distortion of the edge of cap18 the plug 16 is formed with a corresponding groove 20 into which thebead material is pushed when the cap 18 is fitted home, so that this capbecomes locked to the plug 16 and cannot be pulled out therefrom. Toremove the plug the cap 18 must be torn or stripped so that thenecessary extraction rod (not shown) can be screwed into the tapped hole17.

In order to avoid the manufacture of plugs by unauthorized persons, thecap and/or plug material is preferably of such nature that its origincan be ascertained by analysis. To this end, special alloys may be used,or alternately reference substances or elements may be added to thismaterial so that the presence or absence of these substances orelements, determined by appropriate methods, may reveal the authenticityor the falsity of the plug. Of course, the tamper-proof means describedhereinabove is applicable not only to watch cases of the typeillustrated but also to any watch cases having a separate bottom or backcover, whether this bottom or back cover is secured in the manner setforth hereinabove or inserted, screwed or secured by a bayonet system.Furthermore, the tamper-proof means of this invention may be carried outin practice with many modifications and variations without departingfrom the basic principles of the invention as set forth in the appendedclaims.

What is claimed is:

l. A watch case comprising a main body portion and a cover removablyfitted on the main body portion, a blind hole in the outer surface ofsaid .cover forming gripping means for cooperation with cover removalmeans, a plug fitted in said blind hole to normally prevent cooperationthereof with removal means, and a cap of breakable material which isfitted on said plug and which must be at least partially destroyed forremoval of the plug from the blind hole, at least a part of said capbeing substantially flush with the outer surface of said cover.

2. A watch case as claimed in claim 1, in which said plug comprises athreaded hole accessible from outside said cover upon breaking said cap.

3. A watch case as claimed in claim 1, in which said plug comprises anannular groove, an O-ring being compressed in said annular groove by awall of said blind hole to secure said plug in said hole.

4. A watch case as claimed in claim 1, in which said cap comprisesmaterial containing substances capable of being analyzed to ascertainthe authenticity of the cap.

5. A watch case as claimed in claim 1, in which a glass is mounted in abezel formed in said main body portion, said glass being fittable in andremovable from said bezel of the main body portion solely by removal ofsaid cover.

6. A watch case as claimed in claim 1, in which said plug comprises anannular groove, said cap being socket shaped and made in resilientmaterial, at least a part of said cap being compressed in said annulargroove by a wall of said blind hole to secure said plug in said hole.

7. A watch case as claimed in claim 6, in which a skirt-forming part ofsaid cap comprises a shallow bead normally projecting from its outersurface.

1. A watch case comprising a main body portion and a cover removablyfitted on the main body portion, a blind hole in the outer surface ofsaid cover forming gripping means for cooperation with cover removalmeans, a plug fitted in said blind hole to normally prevent cooperationthereof with removal means, and a cap of breakable material which isfitted on said plug and which must be at least partially destroyed forremoval of the plug from the blind hole, at least a part of said capbeing substantially flush with the outer surface of said cover.
 2. Awatch case as claimed in claim 1, in which said plug comprises athreaded hole accessible from outside said cover upon breaking said cap.3. A watch case as claimed in claim 1, in which said plug comprises anannular groove, an O-ring being compressed in said annular groove by awall of said blind hole to secure said plug in said hole.
 4. A watchcase as claimed in claim 1, in which said cap comprises materialcontaining substances capable of being analyzed to ascertain theauthenticity of the cap.
 5. A watch case as claimed in claim 1, in whicha glass is mounted in a bezel formed in said main body portion, saidglass being fittable in and removable from said bezel of the main bodyportion solely by removal of said cover.
 6. A watch case as claimed inclaim 1, in which said plug comprises an annular groove, said cap beingsocket shaped and made in resilient material, at least a part of saidcap being compressed in said annular groove by a wall of said blind holeto secure said plug in said hole.
 7. A watch case as claimed in claim 6,in which a skirt-forming part of said cap comprises a shallow beadnormally projecting from its outer surface.